• Journal of the Korea Society of Computer and Information
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• v.27 no.11
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• pp.115-121
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• 2022

In surface mount technology (SMT), the screen printer, which is an equipment for applying solder cream, has a lot of poor coating as the pad becomes smaller. To solve this problem, a jet printer is being used recently. However, if the nozzle at the end of the valve applied to the jet printer head is not cleaned, solder cream remains or an error occurs. To prevent this, the nozzles should be cleaned periodically. In this paper, a more stable cleaning method than the existing technology is presented for the stable application of solder cream on a jet printer. In this method, cut a 35mm wide mujin cloth, wrap it in a roll, and rotate it with a DC geared motor on the other side to clean it. As a result, it was confirmed that the solder paste was not left on the nozzle surface and was well wiped when cleaning with about 2,000 dotting cycles.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.31 no.1 s.256
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• pp.11-17
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• 2007

In this paper, we present a design, analysis, fabrication and performance test of the novel DoD metal-jet system for application to the high-density and high-temperature-melting materials. The theoretical analysis of the metal-jet nozzle system is derived by using electro-mechanical analogy. Based on the theoretical analysis results, we design the metal-jet print head system and fabricate the metal-jet system, which can eject the droplet of lead-free metal solder in high-temperature. In the experimental test, we set up the test apparatus for visualization of the droplet ejection and measure the ejected droplet volume and velocity. As a result, the diameter, volume and the velocity of the ejected droplet are about 65 $\mu$m $\sim$ 70 $\mu$m, 145p1 $\sim$ 180 pl and 4m/s, which shows quite good agreement with the theoretical analysis results of the 75 $\mu$m-diameter and 220 pl-volume of droplet. In comparison with the experimental result, the errors of diameter and volume are 7% $\sim$ 13% and 18 $\sim$ 34%, respectively.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1450-1451
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• 2008

To investigate the reliability of the conductive lines patterned by ink-jet printing, we evaluated the reliability of the ink-jet printed silver (Ag) patterns according to the guide lines built up as assessments methods in the production of conventional rigid printed circuit boards. The assessment methods include the uniformity of line width and space, adhesive strength, dielectric withstand, solder float, thermal shock test and pressure cooker test (PCT). To prepare assesment vehicles, different regular test patterns were created by Ag ink-jet printing on the same polyimide substrate for each of assessment methods.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.188-190
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• 2004

As an effort to reduce cost and lead-time and to increase flexibility and responsiveness, manufacturers are using digital printing in numerous process steps. Typically, these processes require the precise dispensing of various fluids. Piezo ink jet printheads are proving to be reliable tools for depositing active materials such as light emitting polymers (LEP) for mobile phone displays and color filter inks for liquid crystal displays. Ink jets are also being used to provide uniform coatings of polyimide alignment layers and spacers for LCDs. Success with legend printing on PCBs using ink jets has encouraged the design of equipment for directly printing both etch resist and solder mask for PCBs. Development of printers for passive components such as capacitors and resistors is underway. This paper will present the attributes of an ink jet printhead designed to a precision deposition tool and discuss how it is being used to digitally print electronic and flat panel display components. Status of commercialization of digital printing will be discussed along with issues to be resolved before wide adoption takes place.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.585-586
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• 2006

In this paper, we present a design, analysis, fabrication and performance test of the novel DoD metal-jet system for application to the high-density and high-temperature-melting materials. Based on the theoretical analysis, we design the metal-jet print head system and fabricate the metal-jet system, which can eject the droplet of lead-free metal solder in the high-temperature. In the experimental test, we set up the test apparatus for visualization of the droplet ejection and measure the Ejected droplet volume and velocity. As a result, the diameter, volume and the velocity of the ejected droplet are about $65-70{\mu}m$, 145-180 pl and 4m/sec. We also fabricate vertical and inclined 3D micro column structures using the present molten metal inkjet system. The measured geometries of the micro column structures are about height of $2,100{\mu}m$, diameter of $200{\mu}m$ and aspect ratio of 10.5 for vertical micro column and $1,400{\mu}m$ of height and $150{\mu}m$ of diameter for $65^{\circ}$-inclined micro column, respectively.